Police are warning New Year festival-goers on their way to Gisborne to expect heavy traffic and to drive sensibly.

The annual Rhythm and Vines festival starts tomorrow at Waiohika on the outskirts of Gisborne, while its sister festival BW began in Gisborne City yesterday. Thousands of young people from around the country have been streaming into the city and police say traffic hold-ups are to be expected.

"These two festivals bring around 20,000 extra people into Tairawhiti and that means lots of bodies and lots of cars," Tairawhiti Area Commander Inspector Sam Aberahama said.

"There has been very heavy traffic on the highways over the last few days and we expect that to continue. So we ask that everyone drives sensibly - which means don't speed, be patient and if you feel tired, pull over and have a rest," Mr Aberahama said.

Police will be out in force on the highways in the build-up to New Year, but central Gisborne will also be in for some attention.

One young Auckland youth will not be attending the BW Festival after he drove through a Stop sign last night and straight into a police car. As a result of that, the police car hit another northbound vehicle. All three vehicles were written off and surprisingly, no-one was injured.

The crash occurred at the intersection of Wharerata Rd and Awapuni Rd about 7.45pm.

The youth has been charged with refusing to give a blood specimen. Further charges are likely when the crash investigation is complete. Police say speed and alcohol both appeared to be factors in the crash.

Mr Aberahama said police were pleased with most of the behaviour of those attending BW Festival. Festival organisers have so far ejected 18 people for bad behaviour and numerous others are on final warnings.

"There will be over 7000 young people spread over a very large area and police will be keeping a close eye on the campsites and the concert areas," Mr Aberahama said.

"We have sent out very strong messages about our expectations around behaviour at BW this year. People have been warned that if they cause mayhem or trouble, they will be removed from the festival and not allowed back in."

Police last night issued numerous warnings for breaching the central Gisborne liquor ban that covers public spaces and roads surrounding the festival site. The ban includes the area between the beachfront and Awapuni Rd and ends at Beacon St.